Over the recent past a variety of computer based information systems have been proposed or introduced to the public on commercial as well as experimental bases. These systems have evolved in consequence of the development of large data base computer capabilities and provide for an expanded distribution of information to the consuming public. Certain of the commercial systems are structured for data dissemination via telephonic links from centralized host computer facilities to terminals. Interactive communication is achieved at these terminals through keyboards operating in conjunction with cathode ray tubes and/or printer readout components. In effect, the subscribing operator of such remote terminal keyboards is given access to a highly sophisticated computer system having a very large data bank.
Of course, to effectively use the keyboard terminal, the subscriber must have a reasonable familiarity with the access protocols and related procedures required to carry out an effective dialogue with the host computer facility. These procedures may become somewhat involved in view of the sophistication and versatility of large data base facilities. In efforts to provide accessibility to these information systems on the part of a greater segment of the public, it has become necessary to develop terminal equipment which considerably simplifies the procedures or protocols required to gain access to the host computer. For example, videotex systems have been devised wherein data is displayed at the subscriber's television receiver. Requisite telephonic communication with the host computer facility is carried out through a "user friendly interface" arrangement wherein dialogue protocol are automated and selection of information from the data bank is achieved through menu tree selection indexing. With this indexing technique, a very general, numerically identified categorization of subject matter initially is displayed to the subscriber, one such very general category then being selected by depressing an appropriate corresponding numerical key on the keyboard. Upon such selection, the host computer transmits a next numerically identified categorization of subject matter for display at the subscriber's television screen, such subject matter corresponding to a slight elaboration of the earlier selection. This procedure is continued until the selected subject area becomes so finite as to permit an ultimate selection.
As is apparent, this simplification of the procedure accessing the host data base will become overly time consuming and laborious as the subject matter available at the host facilities increases in extent. In effect, the menu tree indexing approach may itself become so complex as to preclude its practicality.
One highly regarded potential application of videotex systems is that associated with the provision of library services. Subscribers of the service would utilize terminals installed in a home environment or other suitable locations to access a library host computerized reference system. Encyclopedic and other reference materials desired would be accessed and transmitted to the user terminal from the host computer. Where books are desired to be taken out on loan, following the accessing of the host computer through appropriate reference procedures, orders could be placed to the library through the system for mail delivery of books and the like. Thus, the subscriber remotely receives essentially the full complement of library services without the necessity of traveling to the library itself.
To provide such remote library services, however, a practical user friendly interface with the host library computer system would be required. Referencing techniques such as the above-noted menu tree selection indexing may be suited for relatively simple, straightforward request. However, as the user inquiries become more involved to the extent of becoming reference system searches, the simplified procedures heretofore contemplated will, for the most part, fail. For example, the generally unsophisticated subscriber, in effect, becomes interfaced with a highly sophisticated host computer system having data access capability equivalent to the reference floor of a major library. Generally, the typical library patron would look to the expertise of a well-trained reference librarian when encountering a reference facility search requirement. When this expertise of the reference librarian is called upon, a dialogue with the patron ensues wherein the librarian is able to draw out the essence of the subject matter desired. Then, by-passing perhaps large amounts of reference information which the untrained would inaccurately turn to, the librarian will quickly isolate those catalog regions the subject of which is of interest to the patron. While computer accessing techniques may be capable of developing the same isolation of catalogue materials, a sophistication on the part of that person accessing the correspondingly sophisticated computer program is required.
A characteristic of the videotex systems heretofore introduced or proposed has been their dedication to the textual presentation of information. For example, any interaction between the subscriber and host computer has been one wherein text materials are silently displayed on a video screen in correspondence with a silent keypad or keyboard manipulation at the user terminal. While transmission is carried out through the use of modems over telecommunication links, no form of transmission in the audible range has been contemplated as a complement to the textual presentations.